2015-06-01T00:00:00Z, Tuncel, Ilkin, TURP, IŞIL, Usumez, Aslihan, TUNCEL, İLKİN, TURP, IŞIL

Objective: The aim was to evaluate the effect of 1064nm Yb-doped fiber-based nanosecond pulsed laser on surface roughness and bond strength between veneer ceramic and zirconia. Material and methods: Zirconia discs were divided into three groups: sandblasted (SB), laser irradiated (YL), and control (n = 12). YL group was treated with ytterbium laser with the setting of 85W/25kHz. Sandblasting was done using 50 mu m Al2O3 particles from a distance of 10mm for 20s under 3.5atm. No surface treatment was applied to the control group. The surface roughness values and SEM images of the groups were obtained. X-ray diffraction analysis was applied to a spare sample of each group to determine the monoclinic phase ratio. The samples were subjected to shear bond strength (SBS) test with a cross-head speed of 1mm/min after being veneered. The fracture modes were evaluated. One-way analysis of variance and Tukey-s HSD tests were used for statistical analysis. Results: The YL group had higher surface roughness than the control (p <= 0.0001) and the SB group (p = 0.007) with a mean value of 2.90 mu m. The SEM images of the groups supported this result, but formation of the microcracks was more intense for the YL group. The monoclinic phase ratio was highest for the SB group. However, the differences of SBS between SB and YL groups were not statistically significant. Mostly the combined failure of samples was observed. Conclusions: Ytterbium laser treatment increased the surface roughness of zirconia, but the SBS was not higher than sandblasting. Surface roughness results did not correlate with the SBS results.

2017-12-01, TUNCEL, İLKİN, TURP, IŞIL, DÜÇ, Buğra, SELÇUKER, Ahmet Hamdi, ASLANTAŞ, Akif, BEKMAN, Enes, TUNCEL, İLKİN, TURP, IŞIL

2016-06-01, TUNCEL, İLKİN, Turp, IŞIL, USUMEZ, A, TUNCEL, İLKİN, TURP, IŞIL

PURPOSE. The opacity of zirconia is an esthetic disadvantage that hinders achieving natural and shade-matched restorations. The aim of this study was to evaluate the translucency of non-colored and colored framework zirconia and monolithic zirconia. MATERIALS AND METHODS. The three groups tested were: non-colored framework zirconia, colored framework zirconia with the A3 shade according to Vita Classic Scale, and monolithic zirconia (n=5). The specimens were fabricated in the dimensions of 15×12×0.5 mm. A spectrophotometer was used to measure the contrast ratio, which is indicative of translucency. Three measurements were made to obtain the contrast ratios of the materials over a white background (L*w) and a black background (L*b). The data were analyzed using the one-way analysis of variance and Tukey HSD tests. One specimen from each group was chosen for scanning electron microscope analysis. The determined areas of the SEM images were divided by the number of grains in order to calculate the mean grain size. RESULTS. Statistically significant differences were observed among all groups (P<.05). Non-colored zirconia had the highest translucency with a contrast ratio of 0.75, while monolithic zirconia had the lowest translucency with a contrast ratio of 0.8. The mean grain sizes of the noncolored, colored, and monolithic zirconia were 233, 256, and 361 nm, respectively. CONCLUSION. The translucency of the zirconia was affected by the coloring procedure and the grain size. Although monolithic zirconia may not be the best esthetic material for the anterior region, it may serve as an alternative in the posterior region for the bilayered zirconia restorations. [J Adv Prosthodont 2016;8:181-6]

2017-11-12, TUNCEL, İLKİN, OCAK ÇİMENDUR, ÖZLEM, TURP, IŞIL, TUNCEL, İLKİN, OCAK ÇİMENDÜR, ÖZLEM, TURP, IŞIL

2017-10-01, TUNCEL, İLKİN, TURP, IŞIL, TUNCEL, İLKİN, TURP, IŞIL